LOCATION LABISH OREstablished Series
TAXONOMIC CLASS: Fine, smectitic, acid, mesic Cumulic Humaquepts
TYPICAL PEDON: Labish silty clay loam, cultivated. (Colors are for moist soil unless otherwise noted.)
Ap1--0 to 3 inches; black (10YR 2/1) silty clay loam, very dark gray (10YR 3/1) dry; strong fine granular structure; very hard, friable, sticky and plastic; many roots; many very fine interstitial pores; slightly acid (pH 6.4); abrupt smooth boundary. (3 to 6 inches thick)
Ap2--3 to 7 inches; black (10YR 2/1) silty clay, very dark gray (10YR 3/1) dry; weak coarse subangular blocky structure; very hard, firm, sticky and plastic; common roots; many very fine and fine tubular pores; medium acid (pH 5.6); abrupt smooth boundary. (7 to 11 inches thick)
AC2g--16 to 30 inches; very dark gray (N 3/) clay, moist and dry; weak coarse prismatic structure that appears massive when wet; extremely hard, very firm, very sticky and very plastic; few very fine pores; common fibrous roots; very strongly acid (pH 4.6); gradual smooth boundary. (11 to 17 inches thick)
C1g--30 to 48 inches; very dark gray (N 3/) clay, moist and dry, massive; extremely hard, very firm, very sticky and very plastic; few very fine pores; common medium sized, light colored porous soft fragments; very strongly acid (pH 4.6); abrupt smooth boundary. (5 to 25 inches thick)
C2g--48 to 55 inches; very dark gray (5Y 3/1) clay, dark gray (5Y 4/1) dry; massive; extremely hard, very firm, very sticky and very plastic; few very fine pores; neutral (pH 7.0).
TYPE LOCATION: Marion County, Oregon; NE1/4 SW1/4 section 14, T.6S., R.2W.
RANGE IN CHARACTERISTICS: The solum ranges from 24 to 36 inches thick. Depth to bedrock is more than 60 inches. The mean annual soil temperature ranges from about 50 degrees to 55 degrees F.
The A and AC horizons have hue of 10YR through 5Y, value of 1 through 3 moist, 3 or 4 dry and chroma of 2 to neutral. They have moderate to strong fine granular structure in the Ap1 horizon and moderate to weak coarse prismatic structure in the AC horizons. The organic matter in the epipedon is high ranging from about 10 to 25 percent and approaching a histic epipedon. Thin organic layers less than 4 inches thick occur below the Ap horizon in some pedons.
COMPETING SERIES: These are the Bashaw, Chetco and Cove series. Bashaw soils are massive or have weak structure and have slickensides that intersect within the 10- to 40-inch control section. Brenner and Chetco soils lack epipedons that are more than 20 inches thick. Cove soils are slightly to medium acid, have mollic epipedons and have distinct cracks.
GEOGRAPHIC SETTING: The Labish soils are on level bottomlands or basins with impeded drainage. Elevations range from 100 to 200 feet. Slope gradients range from 0 to 1 percent. The soils formed in mixed alluvial or lacustrine material high in organic matter and stratified with thin lenses less than 4 inches thick of peat or much and ranging to thicker peat deposits below 36 inches. The climate is humid temperate. The mean annual precipitation is 40 to 50 inches. The mean annual temperature is 53 degrees F.; the average January temperature is 39 degrees F.; and the average July temperature is 67 degrees F. The frost-free season is 165 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bashaw soils and the Semiahmoo and Wapato soils. Semiahmoo soils are organic soils with more than 30 percent organic matter. Wapato soils have very dark brown A horizons and dark grayish brown moderately fine textured B2 horizons.
DRAINAGE AND PERMEABILITY: Poorly drained; very slow runoff or ponded; slow permeability.
USE AND VEGETATION: These soils are used for onions, pasture, and cereal grains when drained. Principal native plants are tussocks, sedges, ash, willow, cottonwood, and other hydrophyllic plants.
DISTRIBUTION AND EXTENT: Willamette Valley and tributary valleys of central western Oregon. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Marion County, Oregon, 1972.